In general terms, a catalyst is a substance which increases the rate of the reaction being catalyzed without being consumed in the reaction. Stated another way, catalysis is the acceleration of a reaction in the presence of a catalyst.
The activation of a catalyst is sometimes achieved through the absorption of light. A catalyst activated by the absorption of light is termed a photocatalyst.
As known in the industry, photocatalysis can be used to purify water, air and various surface for a variety of applications. Titania (titanium dioxide) has been shown to be a photocatalyst for use in reactions involving many inorganic and organic materials. Examples of these inorganic and organic materials are phenol, aromatics, organic dyes, surfactants, metals, herbicides, pesticides and bacteria.
With regard to photocatalysis, photocatalysts have previously been deposited on a support material. For example, titania has been deposited on non-transparent support materials (such as sand, metal oxides and clays), and the resultant product has demonstrated considerable photocatalytic activity. Titania has also been deposited on transparent support materials such as glass and quartz, but the durability of these deposited titania films is not sufficient for many applications.
Research in this industry has concluded that the support material should possess good optical properties and strong surface bonding with the catalyst without compromising the reactivity of the catalyst.
Therefore, in regard to catalysis and photocatalysis, there is a need for an improved composite which is comprised of an effective catalyst and a good support material.